Heavy rain and strong winds are battering Auckland, with a portable building having been blown off a truck and trees coming down.
The bad weather is hitting much of the country today, particularly the North Island, with winds reaching 138km/h at Hokianga this morning.
Heavy rain warnings were issued for Northland, the northwest ranges of Nelson and the ranges of Westland.
In Auckland, motorists around the city are also being urged to drive to the conditions as a result of the bad weather.
A portable building blew off a truck on the Pātiki Rd off-ramp on State Highway 16 and is blocking the road towards Avondale, West Auckland.
The NZ Transport Agency alerted motorists in the area of the incident just after 9am.
Images show the building almost tipped over the edge of the motorway barrier.
The road has now been closed and people are being told to turn off at the Te Atatū off-ramp or at Great North Rd until the crash has been cleared.
MetService said between 10mm and 16mm of rain had been recorded at weather stations around Auckland in the hour up to 9am. Up to 10mm of rain was recorded at a station in Warkworth.
Aucklanders are being told to expect more heavy rain and strong gusts over the next two hours, MetService said, as a rain band sits over the city just after 9am.
"The heaviest band of rain is mostly sitting over Auckland at the moment," MetService meteorologist Thalia Crabtree said.
"The weather system is moving southeast over the country, but Auckland can expect [bad conditions] over the next couple hours.
"It's starting to ramp up there," Crabtree said.
Strong wind gusts are also causing havoc in and around the city - particularly in exposed area.
The strongest gust recorded on Auckland's Harbour Bridge in the past hour was 83km/h. Winds are even stronger around coastal areas - with gusts of up to 94km/h recorded at Tiritiri.
Crabtree said: "They're pretty strong now [and] there could be some call-outs in the next couple of hours."
The wind coincided with high tide on beaches on the Waitematā Harbour and the sea was rough for anyone brave enough to venture onto the water.
There has been at least one report of a tree brought down in the West Auckland suburb of New Lynn just after 8.30am.
A high of 16C was expected in the City of Sails today and an overnight low of 11C. Gusts of up to 41km/h around the city were also on the forecast.
In Northland, an alert is in place until at least 3pm. At 8.20am, more than 40mm of rain had accumulated at Kerikeri since midnight, MetService said.
People in the area are being told to expect between 50mm to 70mm of rain to accumulate - especially about the eastern hills.
MetService said peak intensities would be between 10mm to 15mm per hour this morning.
"Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are possible and driving conditions may be hazardous," a spokesman said.
There was also a strong wind watch in Northland in the early hours of this morning - with winds turning into severe gales at times. At Hokianga, the wind reached gusts of 138km/h at 6am.
The bad weather comes as a front over the Tasman Sea is due to move southwards over the country today - with a low-pressure weather system set to deepen near East Cape this evening before moving away south.
A strong northeast flow is forecast ahead of that front - bringing with it some heavy rain about northern parts of both islands and also the West Coast, MetService said.
A heavy rain warning has also been upgraded in Gisborne and Bay of Plenty.
The Gisborne District Council is warning locals to stay vigilant and keep up to date with weather alerts today.
People there are being warned that heavy rains may cause streams and rivers to rise rapidly.
"Surface flooding and slips are also possible and driving conditions may be hazardous."
Between 50mm to 70mm of rain is forecast to accumulate - with peak rates of between 10mm to 20mm per hour.
Strong wind watches were also in place for the Bay of Plenty, east of Whakatāne, and Gisborne. A high of 15C was forecast in Gisborne.
People in all those areas are being encouraged to keep a close eye on weather updates throughout the day to make sure they are prepared.
Metservice said the warning for the Coromandel had also been upgraded.
"We're keeping an eye on the rain tracking toward Coromandel Peninsula and Bay of Plenty. Watches for these regions have been upgraded to Heavy Rain Warnings."
For those in Wellington, a high of 13C is on the cards with occasional rain developing this morning and northerly winds.
Dry weather is forecast for eastern Canterbury, WeatherWatch analyst Aaron Wilkinson said.
"Canterbury stays mainly dry - although Otago sees a few showers for a time this afternoon," he said.
The new free open-air saltwater pool is already proving popular.